Oscillating kingpin structure for grain trailer

ABSTRACT

A rocking trailer kingpin assembly for a grain trailer constructed of aluminum or light weight steel includes an upper subframe mounted to the trailer body with a pivotable lower subframe hinged to the upper subframe. The lower subframe includes a skid plate from which a kingpin extends such that the kingpin can be received in the filth wheel coupling, of a truck tractor.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 USC §119 from copendingprovisional patent application entitled OSCILLATING KINGPIN STRUCTUREFOR GRAIN TRAILER, Ser. No. 61/537,262, filed Sep. 21, 2011, Thedisclosures of provisional patent application Ser. No. 61/537,262 arehereby incorporated in their entireties.

BACKGROUND

The conventional grain trailer is equipped with a pin extending downwardfrom the trailer underbody which is fixed to the trailer frame. This pinis received in a fifth wheel coupling on a towing, tractor truck. Onusual street surfaces, the traditional tractor-trailer kingpin couplingis quite satisfactory. However, when the trailer is pulled on unevensurfaces large stresses are experienced by the kingpin and its solidmounting to the trailer underbody frame.

As fuel costs have risen, efforts to reduce operation costs for graintrucking activities have led to grain hauling trailers being designedwhich can be manufactured from lighter weight materials, particularlyaluminum and light weight steel. When aluminum or light weight steel areused for grain trailer bodies, the mounting of the kingpin to the frameis unable to stand up to the stresses on the mounting when the traileris pulled over uneven surfaces, particularly over grain fields, wheregrain trailers are often used. Twisting forces on the trailer body as itis towed over a grain field tends to heavily stress the trailer'sstructure, particularly when the trailer's kingpin is solidly fixed tothe body. The stresses from such twisting are less well tolerated whenaluminum or light weight steel is used in the stricture or when thetrailer body is assembled by use of rivets instead of welding.Therefore, to afford improved fuel economy through reduction in trailerweight while maintaining the useful life of the trailer, development ofstructure to reduce the twisting stresses on the trailer body has beenneeded.

SUMMARY OF THE INVENTION

The present invention provides an improved kingpin assembly for mountingto a trailer, particularly to a grain trailer constructed of aluminum orlight weight steel which is pulled over uneven surfaces such as a cropfield. The kingpin assembly includes a steel upper subframe which mountsto the underside of the grain trailer at the front end of the trailer,the existing kingpin post of the trailer having been removed. A steellower subframe is hinged to the upper subframe and a kingpin extendsdownward from a skid plate of the lower subframe. The kingpin can bereceived in the fifth wheel receiver on a truck tractor used to tow thetrailer.

The lower subframe is hinged to the upper subframe by axle members whichlink upstanding frame elements of each of the upper and lower subframes.Resilient bumper elements are mounted to the upper surface of the lowersubframe which cushion the abutment of the lower subframe to theunderside of the trailer as the kingpin assembly rocks as the trailerpasses over uneven ground surfaces.

It is a primary object of the invention to provide an improved kingpinassembly for a grain trailer constructed of aluminum or light weightsteel, to allow the grain trailer to rock relative to the truck tractorpulling it without overstressing the kingpin inserted within the fifthwheel hitch of the truck tractor.

It is a further object of the invention to provide an improved aluminumgrain trailer which can withstand twisting forces occurring when thetrailer is towed over uneven ground surfaces.

It is still a further object of the invention to provide an improvedgrain trailer which allows rocking of the trailer relative to a trucktractor to which it is coupled by a kingpin inserted in the fifth wheelhitch of the truck tractor.

These and other desirable objects of the invention will be understoodfrom reference to the drawings and to the detailed description of thisspecification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an enlarged perspective of a front portion of the underside ofa grain transporting trailer equipped with the invention.

FIG. 2 is a top perspective of the invention.

FIG. 3 is a bottom perspective of the upper subframe member of theinvention.

FIG. 4 is a top perspective of the lower plate member of the invention.

FIG. 5 is a front elevation of the invention at rest.

FIG. 6 is an elevation of the invention tilted in a first direction.

FIG. 7 is an elevation of the invention tilted in a second direction.

DETAILED DESCRIPTION

The present invention provides a solution to reduce mechanical stresseson the kingpin and underbody frame structure of a grain trailer to betowed by a truck tractor equipped with a fifth wheel coupling,especially when the grain trailer is towed over an uneven surface suchas a crop field. More particularly, this invention is useful when theframe structure of the grain trailer is constructed of aluminum or lightweight steel.

FIG. 1 illustrates the kingpin structure 2 mounted to the underbody 5 ofa grain transporting trailer 3. The kingpin structure 2 comprises alower mourning plate 10 to which the kingpin 12 is securely mounted. Thelower mounting plate 10 is moveably secured to an upper mountingsubframe 14 which is bolted to the underbody 5 of trailer 3. The uppermounting subframe 14 is received within the main frame 7 of the trailer3 forward of the landing gear 9 spaced a short distance behind the fromwall 11 of the trailer frame 7. A spacer 45 is sandwiched between lips42 and frame 7. Kingpin structure 2 is preferably made of steel.

Referring now additionally to FIGS. 2-3, it can be observed that uppersubframe 14 comprises an open rectangular frame 16 including front endwall 18 and rear end wall 20 joined by opposing first and secondsidewalls 22, 24. First transverse rib 26 and second transverse rib 28interconnect sidewalk 22, 24 and are substantially parallel to end walls18, 20. Diagonal brace members 30, 32 join rear end wall 20 to secondintermediate rib 28. Struts 34, 36 provide rigid separation of secondtransverse rib 28 from first transverse rib 26.

Secured between front end wall 18 and first transverse rib 26 is pivotsupport 38 which is generally centered between side walls 22, 24 andincludes rib braces 39, 40 which also maintain rigid, separation offirst intermediate rib 26 from front end wail 18.

Each side wall 22, 24 is provided with a lip 42 running the lengththereof, extending outwardly from the lower ends 23, 25 respectively ofside walls 22, 24. Openings 44 are spaced along the lengths of lips 42to receive fasteners to secure a strip of nylon or plastic to each lip42 as spacer 45 between the subframe 14 and frame 7 in order to reducecorrosion potential between the steel of subframe 14 and the aluminum oftrailer frame 7.

Subframe 14 is retained to trailer frame 7 through use of lateral bolts46 (See FIG. 1) which are passed through the skirt 15 of frame 7 andinto sidewalls 22, 24 of upper subframe 14. Holes for lateral bolts 46are made at time of installation. Subframe 14 is positioned with itsfront end wail 18 spaced away from front wall 11 of skirt 15 of trailerframe 7.

A first hinge element, pivot support 38, is welded to first intermediaterib 26 and to front end wall 18 including at attachment legs 50. Eachattachment leg 50 is part of a side brace 39, 40, the side braces 39,40each including receiving slot 41 into winch front wall 18 resides, withattachment legs 50 disposed on the outside of front wall 18. Side braces39, 40 and the attachment legs 50 thereof are securely welded toopposing sides of the front wall 18 while side braces 39, 40 are eachalso welded to intermediate rib 26. Pivot support 38 includes front andrear bearing support plates 52, 54 which include pivot bearings 56, 58therein. Bearing support plates 52, 54 are aligned in the same planewith front wall 18 and first intermediate rib 26 respectively.

Referring now to FIG. 4, the lower mounting plate 10 is rectangular,preferably square, and includes an underside skid plate 60 havingupturned front and rear edges 62, 64. On the top surface 61 of skidplate 60 is securely mounted second hinge structure 66 which comprisesfront and rear axle receivers 70, 72 which are identical and arrangedwith on mirroring the other. Each axle receiver 70, 72 comprises a pairof closely spaced apart upstanding arched plates 74, 76 having axleopenings 78 therethrough. Each axle receiver 70, 72 is welded to topsurface 61 of skid plate 60 on an opposing side of kingpin receiver 68which is generally centered on lower mounting plate 10. Kingpin receiver6$ may he internally threaded to receive kingpin 12.

Kingpin receiver 68 is surrounded by reinforcing structure 98 which inthe preferred embodiment of FIG. 4 comprises an upstanding box andgusset brackets 93 joining the inner arched plates 76.

Outer curved plates 74 are reinforced by outrigger gusset brackets 81.Gusset plates 80, 82 provide rigidity to the rear corners of lower plate10. Robust stop bumpers 84 (See FIGS. 2, 5-6) are mounted to lower plate10 and are disposed to abut the underside of front end wall 18 and thefirst intermediate rib 26 when lower mounting plate 10 rocks about axles90 which are receivable in each pair of axle openings 78, 79. Pins 92are provided on longitudinal side reinforcing ribs 94, 95 to providemounting elements to receive the stop bumpers 84.

Second hinge structure 66 also includes transverse ribs 86 andlongitudinal frame members 88 which are welded to the top of skid plate60.

Second hinge structure 66 also includes transverse ribs 86 andlongitudinal frame members 88 which are welded to the top surface 61 ofskid plate 60.

Each axle receiver 70, 72 surrounds a bearing support plate 52, 54respectively when lower mounting plate 10 is raised to the underside ofupper subframe 14 and axle openings 78, 79 are aligned with pivotbearings 56, 58. An axle 90 may be inserted through each set of axlereceiver 70, 72 and each pivot bearing 56, 58 respectively to retainbearing plates 52, 54 to axle receivers 70, 72 such that lower plate 10may pivot over a limited range on upper subframe 14. When assembled tosubframe 14, a portion of lower plate 10 extends forward of front endwall 18 such that kingpin receiver 68 is disposed below the spacebetween front end wall 18 and first intermediate rib 26 of uppersubframe 14.

Axles 90 are coaxial and parallel o the longitudinal centerline of thetrailer frame 7.

Referring now to FIGS. 5-7, the oscillating range of kingpin structure 2is shown with illustrations how lower mounting plate 10 and kingpin 12rock relative to the upper subframe 14. Lower plate 10 is allowed torock around pivot axles 90 to the extent that nylon stop bumpers 84 abutthe from wall 18 and first intermediate rib 26 to prevent furtherrotation of lower plate 10 about axles 90. Therefore, the trailer 3 isfree to rock. relative to the fifth wheel hitch of the truck tractorwhen the trailer and truck tractor pass over uneven surfaces whilejoined.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it should be understoodby those of ordinary skill in the art that various changes,substitutions and alterations can be made herein without departing fromthe scope of the invention as defined by appended claims and theirequivalents. The invention can be better understood by reference to thefollowing claims. For purpose of claim interpretation, the transitionalphrases “including” and “having” are intended to be synonymous with thetransitional phrase “comprising”.

What is claimed is:
 1. Coupling apparatus for a grain trailer comprisingan upper subframe fixed to the underside of a frame of the graintrailer, the upper subframe including a pivot support secured thereto,the pivot support comprising first and second spaced apart bearingsupport plates, a lower plate member pivotably retained to the uppersubframe, the lower plate member comprising a kingpin dependingtherefrom, a pair of spaced apart axle receivers fixed to and extendingabove the lower plate, an axle passing through the axle receivers of thelower plate and also through bearings supported in the bearing supportplates of the upper subframe, wherein the lower plate will rock aboutthe axle.
 2. The coupling apparatus of claim 1 wherein the pivot supportsecured to the upper subframe between a front end wall and anintermediate rib of the subframe, the pivot support comprising first andsecond bearing support plates, the first bearing support plate dependingfrom the front end wall of the upper subframe and the second bearingsupport plate depending from the intermediate rib of the upper subframe,a lower plate pivotably retained to the upper subframe, the lower platecomprising a kingpin depending therebelow, a pair of spaced apart axlereceivers extending above a skid plate of the lower plate, an axlepassing through the axle receivers of the lower plate and also throughbeat mg supported m the bearing support plates of the upper subframe,wherein the lower plate will rock about the axle relative to the uppersubframe.
 3. In a coupling apparatus for a grain trailer wherein akingpin on the grain trailer is received in a fifth wheel hitch of atruck tractor, an improvement comprising a steel upper subframe securelymounted to an underside of a grain trailer body near a front endthereof, the grain trailer body constructed of aluminum, the uppersubframe including a first hinge element depending therefrom, a lowerplate member including a second hinge element, the lower plate memberconstructed of steel, the second hinge element coupled to the firsthinge element by at least one axle wherein the second hinge element ispivotable on the first hinge element about a generally horizontal axisdefined by the at least one axle, the generally horizontal axisgenerally aligned with a longitudinal centerline of the grain trailerbody, the lower plate member comprising the kingpin depending therefrom,wherein the lower plate will rock about the at least one axle relativeto the upper subframe.
 4. The improvement of claim 3 wherein the lowersupport plate member includes a skid plate, the skid plate having a topsurface, the second hinge element fixed to the top surface of the skidplate, a kingpin receiver disposed generally at a center of the skidplate, the kingpin received in the kingpin receiver.
 5. The improvementof claim 4 wherein the first hinge element comprises first and secondspaced apart axle housings, the first axle bearing housing spaced apartfrom the second axle bearing housing, each axle bearing housingincluding an axle bearing, the second hinge element comprising at leasttwo axle receiving plates upstanding on the top surface of the skidplate, the at least two axle receiving plates spaced apart a distancegenerally equal to a distance between the first and second spaced apartaxle housings of the first hinge element.
 6. The improvement of claim 4wherein the second hinge element comprises two pairs of axle receivingplates upstanding on the top surface of the skid plate, each axlereceiving plate of each pair of axle receiving plates including an axleopening therethrough, a first of the axle receiving plates of each pairof axle receiving plates spaced a small distance from a second of theaxle receiving plates of each pair of axle receiving plates, the fastand second of the axle receiving plates of each pair of axle receivingplates defining a gap therebetween, the first axle housing of the uppersubframe receivable within the gap defined by the first and second ofthe axle receiving plates of the first pair of axle receiving plates,the second housing of the upper subframe receivable within the gapdefined by the first and second of the axle receiving plates of thesecond pair of axle receiving plates, the at least one axle comprisesfirst and second axles receivable in the axle receiving plates and thebearing housings.
 7. The improvement of claim 6 wherein the uppersubframe comprises a front wall and a rear wall interconnected by sidewalls, the upper subframe further comprises a first intermediate rib anda second intermediate rib, each of the first and second intermediateribs generally parallel to the front wall, the first hinge elementmounted between the first intermediate rib and the front wall, the uppersubframe spaced apart from a front wall of a frame of the grain trailerbody.
 8. In a grain transporting trailer having a kingpin which isselectively receivable in a fifth wheel hitch of a truck tractor, animprovement comprising: a coupling apparatus for mounting to anunderside of a frame of the grain transporting trailer near a front endthereof, the frame constructed of one or more of the group consisting ofaluminum and light weight steel, the coupling apparatus including afirst hinge element depending from the underside of the frame, a lowerplate member including a second hinge element, the second hinge elementcoupled to the first hinge clement by at least one axle wherein thesecond hinge element is pivotable on the first hinge element about agenerally horizontal axis defined by the at least one axle, thegenerally horizontal axis generally parallel with a longitudinalcenterline of the frame of the grain transporting trailer, the kingpindepending from the lower plate member, wherein the lower plate will rockabout the at least one axle relative to the underside of the frame ofthe grain transporting trailer.